1. Field of the Invention
The present invention relates to a cap member of a swing arm for a rear wheel of a motorcycle or the like.
2. Description of the Related Art
A motorcycle is structured such that a swing arm for a rear wheel is supported on a vehicle body frame so as to freely oscillate in a vertical direction, the rear wheel is rotatably supported on a rear end of the swing arm, a drive chain is wound around a drive sprocket coaxially attached to the rear wheel, whereby a driving force is transmitted to the rear wheel.
As shown in FIG. 11, an adjuster 101 for a drive chain of a rear wheel of a vehicle is inserted to a rear end inner portion of a swing arm 100 for the rear wheel, and a cap member 102 for closing a rear end opening of the swing arm 100 is attached thereto. The adjuster 101 is structured such that a rear axle 103 for the rear wheel passes therethrough, an adjusting bolt 104 of the adjuster is protruded to a rear side of the swing arm 100. The adjusting bolt 104 protrudes from the swing arm 100 through the cap member 102. The cap member 102 is formed in a flat plate shape, and receives an adjusting nut 105 engaged with the adjusting bolt 104 by a rear end surface so as to support the adjuster 101. A tension of the drive chain is adjusted by screwing the adjusting nut 105 forward or backward and executing fine adjustment of a longitudinal position of the adjuster 101.
Japanese Unexamined Utility Model Publication No. 64-37794 also discloses an adjuster for a drive chain which is approximately similar to the one shown in FIG. 11.
In this structure, it is necessary that the cap member 102 be provided with a certain degree of rigidity for receiving a load from the rear axle side via the adjuster 101. Accordingly, the cap member 102 has a certain degree of thickness, and has a great weight in spite of being a simple part.
Further, since the swing arm 100 to which the cap member 102 is attached is formed such that its rear end is cut by a flat surface, and gives an impression that it breaks in the middle, it is hard to say that the swing arm 100 has an excellent outer appearance.